Iron Removal & Softening
For working as a test engineer these past many years, I can’t seem to help but complicate even the simplest task. Take, for instance, choosing a water softener for our home. Rather than simply agree to buy whatever product the local dealer happened to sell, I felt a compulsion to instead specify and build the system myself.
The process took quite a bit of research. But I am fully happy with the result. The project is now, at very long last, wholly installed, fully complete, and functioning well. It took much longer than it should have, being interrupted by a couple of surgeries. Still, even so, I did it all by myself. Nothing has been minimized. No short-cuts taken, no trade-offs made.
Terms employed in this record of my well-water treatment project:
Some related terms not pertaining to my own installation.
How much contaminant can a unit volume of any given resin absorb? A confusing the issue is that there are two ways to measure: the global standard, and the American way.
HTML Off-site link fully explaining ion exchange capacity.
In chemistry, one equivalent has the value of one mole of ionic charges, be that either cations or anions. The same unit, therefor, regardless of whether acid or base, no matter which acid, or which base. This because of being divided by the valence of said ion, whichever it is. A mole’s worth of either H+ or OH-. One half mole’s worth of SO42-. One third mole’s worth of Fe3+. And so on. A true standard, exact and precise, good for all cases.
Here the unit eq is quantified as one liter of liquid volume. Fully regenerated resin under working conditions. That is to say, while saturated with absorbed water. Sometimes it lists as eq/L so as to avoid confusion with a hand-written numeral 1. Find it listed in PDF spec sheets for resins from global suppliers.
Compare against US units like so: 1 eq/l = 21.87 Kgr/ft3.
Here the unit eq is quantified as dry weight. The resin wholly absent of absorbed water. It’s capacity while still in an unopened bag.
I have yet to find a published conversion value.
Water hardness has plural comonents, of which calcium carbonate (CaCO3) is the larger. Pretending as if CaCO3 were the one and only, its weight in grains (1/7000 lbs) can serve as a measure to stand in for all. Then to avoid too many trailing zeros, the quasi-metric kilograins (1000 gr) is often employed.
Suppose I might want to quantify the fruit in a bowl having 10 apples, 4 oranges, 13 grapes, and one banana. How do I measure? Obviously, I weigh the whole bowl, dividing that by the weight of one apple. Viola! I now have a bowl of just only apples. Makes perfect sense.
Quantifying for volume, resin capacity can then be expressed as Kgr/cu ft. Which is to say, how much CaCO3 could that much resin absorb. If, that is, CaCO3 was all that there is. Which it isn’t. Nevertheless, find this ‘unit of measure’ listed in spec sheets from US distributors.
Compare against the metric standard like so: 1 Kgr/ft3 = 0.0457247 eq/l.
References: https://www.seplite.com/softening-demineralization-power-industrial.html
Aimed at removing just only certain cations: Ca2+ and Mg2+, sometimes also Fe3+.
Targets removal of all these cations: Ca2+, Fe3+, Mg2+, Mn2+, K+, Na+. Also these anions: CO2-, HCO3-, Cl-, NO3-, SO42-, SiO2
No matter how close to one another, no two wells give quite the same water. Here are the symptoms I was wanting to cure.
A wee bit of on-line research informs anyone how to diagnose certain well-water symptoms before an expensive laboratory analysis.
While not a health hazard, these microorganisms are a nuisance otherwise. They feed on iron in one of two ways.
The chief nuisance to underground wells are those which feed by chemically reducting Fe3+ compounds down to lower-eneregy Fe2+ compounds. Or, should dissolved Fe3+ be lacking, then instead reducing Mn4+ down to Mn2+. This they can do even deep undergound with no light at all and hardly any dissolved O2.
Another variety feeds in the opposite way, by oxidating Fe2+ compounds up into Fe3+ compounds. As this process requires abundant O2, these bacteria are more to be found in surface waters.
Both types alike consume their preferred valence of metal ions from compounds dissolved in the water they popuplate while precipitating insoluble metal compounds (more detail here: Ref. PDF). And it is these insolubles which leave stains: orange in the case of Fe; black if instead Mn.
Cool temperatures underground limit the growth of either kind. Once afforded warmth and free air, both kinds will flourish to their utmost. A colony of the reducing sort is easily distinguised as feathery redish-orange slime. The oxidizing variety is known to plug roadway storm drains. Both kinds adhere very well to plastic, preferring it over other surfaces for some reason. Examples would be: toilet tank flapper valves; corrigated sewer pipes; and ironically, the upper distributor baskets of air-injected iron-removal tanks.
Very often co-occurring with iron bacteria are also these microorganisms. Breathing in sulfate (SO42-) compounds, these poop out reduced-sulfur variants. Hydrogen Sulfide (H2S) is one such, the noxious gas which rotten eggs smell of.
Hence that unpleasant waft when first I’d turn on a tap in the morning. A small slug of water is always trapped above any turned-off valve. Afforded free air at the top, and not at risk of drying out, it’s bacteria party time until the next turn-on.
Certain strains are reportedly associated with diseases of the human lower bowel. Less from direct action agaisnt human tissues than from their by-product of irritantating H2S gas. One supposes that rotten-egg farts must surely be a notable symptom. If suffering this, co-workers would have long-since informed me (some of them not very politely).
As for these only recently did I very much notice them. Not until a new water heater got installed, attended with some banging on pipes. Being black, they would seem to be particles of MnO2. Because, although preferring dissolved Fe, once that runs out, metal-reducing bacteria will turn to dissolved Mn as second choice.
Possibly hematite (Fe2O3), which can show in a range of colors: more commonly reddish-brown, but sometimes also plain brown, gray, or even black. Definitely not magnetite (Fe3O4) though, for not reacting to a magnet. Most probably MnO2, therefor.
Or maybe just crud, since any significant amount of MnO2 coating my pipes had aught to catalyze dissolved Fe2+ ions straight away into insoluble oxide. Which would tinge my water orange straight out of the tap. Because that, after all, is how most iron-removal water treatment works. Unless there is maybe not sufficient dissolved O2 in my well water from a mere 42 feet down. So a bit of a mystery, still, those little black specs.
At a cost of about $200-plus each, I have had my well’s output tested on two occasions: on 2012-09-08 (5 months after drilling), and again eight years later on 2020-08-12. Both were performed by National Testing Laboratories. The differences are as show below, given as mg/L (same as saying PPM):
Also these:
Noteworthy among those numbers is the content of Calcium (Ca) and Magnesium (Mg), these being removable by ordinary softener media; plus the Iron (Fe) and Manganse (Mn), those removable by a separate tank containing Katalox Light filter media; and also the Turbidity and Tannins, those being filterable. And the all-important pH ≥ 7.
The high sodium and chloride are doubtless from the tons of salt dumped on roadways by the county to melt ice in winter. Also from everyone else’s water-softening systems, each spewing out many gallons of brine each re-generation. Which latter rank, we ourselves are soon to join, alas and alack. But not into our septic tank, as many do. Here my engineering skills will come most into play.
The well itself is 8 years old, drilled through 42 feet of almost pure sand until reaching clay. A 6-inch casement with a 20-foot drop, a 1/2HP Sta-Rite pump, with 5gpm output. Better than average for hereabouts, put in by Koops Well Drilling when I purchased the house. The original well had been condemned by Ottawa County Health for being in the basment (no longer allowed), and also too shallow (just only 12 feet).
Not bad water, really. No coliform bacteria, pesticides, etc. But neither report had a line item iron- or sulfate-reducing bacteria (they being deemed not harmful?)
To properly size a water treatement system, one must first know the available flow rate. It must be enough to lift and swirl media inside the mineral tank (which can be heavy). I calculated for our home per the recommended method helped by my wife Karin. Steps were as follows:
Step 1 of 2
Step 2 of 2
Calculation
As a sanity check, I made plural connections from just the bathtub only. Each opening of the single-lever spigot was to the half-way point at 12 o’clock. Warm water, therefor.
Bathtub Only
I sent my water report to several water-treatment vendors. Their recommendations group as follows:
Most of my neighbors go with the cheapest of all possible options: an ordinary water softener re-generated with Morton Iron-Treatment salt. Which does work, mostly. It certainly gets out most of the iron. But still it leaves some (as my closest neighbor attests). This whereas I am wanting all the iron out. FYI: the special additive in that salt is really just food-grade citric acid. Thought I would mention.
The first vendor I contacted recommended a single tank containg a stratified 5-component media called Ecomix-C. A still-simple system that would get even more iron out.
A 1st-stage pre-treatment with Katalox Light media, upgraded with an ozone-injector. This for delivering a one-two punch to both kinds of iron bacteria (reducing and oxidizing). Firstly starve them of food (dissolved iron). Secondly poison them with ozone.
Then a 2nd stage to deal with hardness in the most usual and ordinary way.
Curiously, none of the vendors recommended a whole-house activated carbon filter. Probably due to an absence of pesticides, heavy metals, etc. in my well water.
Much touted by some vendors is upflow regeneration. Animated videos portray the claimed advantages. Namely, that unexhaused resin at the tank’s bottom suffers exposure to hardness ions driven down from above. The Clack CS, WS1, and TC valves all allow for this option, as does the Nelson C-Series Clack valve. Most others do not, as his option requires extra components within.
The argument does seem convincing do a degree. However, the resin life gained is a mere 5%. Not insignificant, media bed service life 1/20th longer. However, I read it elsewhere reported that when used on well water, the sediments (from iron or tannins) thereupon slowly coat the valve body over time, it being at the top of said up-flow. Which, if it happens, can only be cured by an otherwise wholly unnecessary “acid wash” to restore proper flow.
Further, i is noteworthy that the OEMs for most resin types publish service-life ratings only for coflow (aka down-flow) regenerated systems. Zero mention is made of up-flow. Thus I decided upon the more usual down-flow regeneration.
Here is information on various media. Firstly the three which I chose for my own system.
Would solve my issues with Fe, Mn, and H2S. Of all MnO2 based media, this one weighs least. Consequently backwash flow rate is lower. Manufactured by Watch Water in Germany, relevant documents may be got here: LINK
As my water report listed total dissolved Fe at only 1.26 ppm, the SST-60 softener beads alone would likely have coped. None of my immediate neighbors include a separate Fe-removal tank in their own softening systems. Instead they guard against Fe-fouling of their softener media by means of special salt (containing citric acid). Some occasionally re-charge their softer with a much harsher chemical (sodium hydrosulfite) sold for the purpose in all the local hardware stores.
Not until sometime later did I learn how to shock-treat my well with chlorine bleach (a separate topic detailed below). Which all by itself wholly dealt with the iron problem. Namely all the pipes of my house having slowly become colonized by iron-eating bacteria through the negligence of prior owners. A process, however, needing repeated application at least twice a year.
At the time of my purchase decision, rust stains in both the shower, dishwasher and washing machine had become a great annoyance. So I do not at all regret the extra expense. Certainly my wife is happy, as no longer need we warn guests about the danger our washing machine might pose to fine Irish linnen.
Calgon OLC coconut shell carbon.
The SST stands for Shallow Shell (sometimes dumbed down as Salt Saving) technology, offering high-efficiency regeneration. The (sometimes missing) C indicates cation. A strong base cation media. Highly resistant to iron fouling. More expensive by 10%.
HTML Link to off-site page.
Fe-removing salt contains citric acid. Manual cleaning involves sodium hydrosulfite at 1.25 pounds per ft3 of resin. Pure salt (sodium or potasium chloride) can be user-augmented with citric acid purchased in bulk.
A 5-part, self-stratifying mix effective on both Fe and NOMs. Sounds ideal. Alas, there are a couple of gotchas.
Regarding strata 4-of-5 in the mix, Ecomix literature lists two warnings:
Bit of a Catch 22, the above, since...
That said, one email informed me as follows: oxidizers damage crosslinking in the chemistry of all resin media, resulting in their gradual breakdown. Said email dismissed mere airation as too weak of an oxidizer for any concern. It made no mention, however, of O3, about which I had specifically asked.
An activated carbon tank immediately upstream would go a long ways toward shielding Ecomix-C from trace amounts of oxidizers, however.
Regarding strata 1-of-5 in the mix, gravel is useless and inappropriate if choosing an Empress Vortech mineral tank. It can, however, be separated out, as below. An Ecomix vendor even offered to do this for me.
Some on-line brochures name this strata quartz sand. The German OEM’s website lists it simply as gravel.
Layer 5-of-5 is beads that float, congregating always around the top basket. Without them, during backwash, the light-weight FerroSorb layer below might rise to high, compacting against the top basket. Avoided is a a poor backwash from temporarily restriction of flow, and possible media loss.
Some on-line brochures claim this strata removes oxidized iron. The German OEM’s website says merely that it enhances backwash. No advertisement depicts these beads floating. The opposite, rather.
Ineffective against H2S. But once again, activated carbon upstream would deal with any H2S.
An acronym for “Burgess Iron Removal Method”. This media is Aluminum Silicate impregnated with manganous salts.
Heavy. High-volume backwashes. Ineffective against H2S. Requires pH 6.8-9 and 15% dissolved O2 to work.
Industrial cousin to SSTC60. The H stands for H+, meaning that regenerating this requires acid rather than salt.
One vendor tauts this most stridently as the ultimate, absolute last word in softening media. It requires only water, not any salt. It never wears out, being active ingredient through and through. All true facts.
Very heavy. Requires nightly, horrendously high-volume backwashes.
A strong base anion resin. Removes NOMs in addition to demineralizing. Retards acid (a problem I don’t have @ pH 7.6). Excellent resistance to organic fouling.
Clean CaCO3 precipitation with citric acid. Add 0.5 to 1 pounds of soda ash (Na2CO3) to the brine. This will increase pH causing the resin to swell, increasing pore diameter, allowing more of the tannins can be eluted. Tannins also are more soluble at the higher pH, helping to strip them out. This cleaning procedure can produce the fishy odor, so that a second regeneration should be performed, converting the resin completely to the chloride form.
Needs own separate softener downstream. Quite expensive: $450 per ft3 sack.
I have read nothing but good things about both Clack and Fleck, but with the former given praise highest of all. Of some other brands, I’ve read occasional poor reviews. Of yet others, no independent reviews whatever.
That said, some models are really either one or the other above despite claims to the contrary. As a for-instance, Sterling brand water softeners are topped by valves marked only as Sterling, which are also silver-gray rather than black in color, but which otherwise bear an identical twin appearnace to Clack in every other particular.
Thus I was originally convinced that the Clack model WS1EE aught serve my needs well. The EE model particularly, as that style can be directly mated to an ozone-generator of equally good repute. Likewise, should I go with an on-demand (two-tank, alternating) softener system, there is also the Clack model WS1EE-Twin.
Then I read of Nelson Water Systems, who offer a very exclusive 5-button model of the Clack WS line. These come very highly recommended indeed, the only trouble being that I could not purchase one anywhere as Neslon sells only to licensed installers. At least it is so in the USA. A roadblock which I easily detoured around by purchasing instead from a vendor in Canada. Said vendor supplied me also with the Nelson documentation as PDFs.
Clack Nelsen NWTS 5 Button Control Valve - AIO, Metered: $395.
Ozotech EOG Nelson Field Kit: $349
Atop 10x54 Enpress Vortech tank holding 1.0 ft3 Katalox Light, in first position.
Clack Nelsen NWTS 5 Button Control Valve - Filter, Time Clock: $325
Atop 10x54 tank holding 1.5 ft3 Calgon OLC 12-40 mesh carbon, in middle position.
Clack Nelsen NWTS 5 Button Control Valve - Softener, Metered: $395
Atop 10x54 Enpress Vortech tank holding 1.5 ft3 Purolite SST-60
, in last position.
This is a unit for generating ozone for the re-generating Katalox Light. Just plain air might also work, did I not have iron-reducing bacteria. There was one horror tale which I read of, compelete with photo, of a Katalox Light mineral tank, its Fleck valve lifted up to show the top basket thickly encrusted by iron ochre. See photo below.
The bacteria, so I have read, attach themselves very well to plastic. This I got from a county government report on iron-ochre bacteria actually clogging the rain-water drain systems beneath roadways. Said blockages were more prevalent inside of plastic pipes than in pipes of either iron or concrete.
Ozone, then, seems entirely worth the extra expense.
The GPM of required back-wash is calculated on media surface area, not volume. So a 9-inch tank having 0.442 ft2 versus a 10-inch tank having 0.545 ft2 has 81% as much surface area and so will consume 19% less water and salt each and every re-generation.
On the Terry Love water-softener forum LINK, the well-known member "Reach4" provided me spreadsheet charts factoring these two size tanks in terms of required GPM at different tempratures for a range of bed expansions.
Still, in the end, the Canadian vendor recommended very convincingly Enpress Vortech tanks in size 10x54. The larger tanks are appropriate to standard 1.0 and 1.5 ft3 measures of media. And Enpress Vortech tanks have a custom distributor at bottom which is 30% more efficient than ordinary tanks with their basket and bed of gravel at bottom. So I went with those.
I had wanted unpainted tanks, the better to use a flashlight for monitoring the uplift-and-swirl of media beds during regeneration. This would have meant a special order, however, and thus long delays. At the Canadian vendor’s suggestion I chose almond color tanks. And these, indeed, proved sufficiently translucent for monitoring by flashlight.
On-line I see media tanks painted mostly a wholly opaque, dark blue or black. This would make monitoring impossible; and so seems to me a serious design flaw. You cannot know whether a calculated blackflow rate is agitating the media bed sufficiently. Nor yet, and very much worse, incrementally flushing a portion of media beads down the drain with every regneration, until at last there are none.
The Canadian vendor made this suggestion: to use only 1.0 versus 1.5 ft3 of media. The reasons given were these.
Just only a few softener installation manuals have I yet read, but so far they all agree on one point. The drain line needs to be as short, and also lead down. If leading any distance away, then it needs to be larger.
At time of purchase, the house came with a non-functional water softner. Homeowner installed, its drain line ran up to split at a tee where were paired shutoff valves labeled ‘Winter’ and ‘Summer’.
The ‘Summer’ drain line reputedly conducted backwash to a small ornamental pond quite some distance away. Ornamental in name only, this was quite delapidated, its purely-for-looks little arch bridge falling apart. Said ‘Summer’ drain line, if truely it did lead all that long way still terminated some few feet above basement floor level.
The drain labled ‘Winter’, as my hired home inspector did point out, conducted to the home’s highest septic line terminus via a drilled-through cleanout cap, the juncture sealed with gobs of silicone.
Might this be part of the reason why the unit no longer functioned?
Nearly all of those neighbors I have questioned report their own water softener drain lines as leading to their septic tank only, or else having a ‘Summer’ line conducting to someplace outdoors. But as for me, I could not imagine that salt put into the septic tank could not be a very good thing.
Firstly, salt is a preservative. We use it, after all, to prevent things from spoiling. At very much higher levels, true. And true as well, that there are bacteria which live in the super salty Dead Sea. But those are different bacteria than hopefully flourish inside my septic tank one mile inland from Lake Michigan. But salt as bacterial inhibitor, so I have since read, is much the lessere lesser of two septic tank worries.
Salt water is much denser than fresh. Being heavy, on pouring into the septic tank guess where it heads? Straight to the bottom. And there it stays. Rinse water from the softener regeneration cycle following after isn’t nearly so heavy. Thus it does not head straight to the bottom. And so fails to dilute the salt water which went just only some moments before.
And for sitting there at the bottom, what does salt water do? It makes to float higher all those contents which aren’t salt water. And if made to float high enough, scum and solids will get into the drain field. And wouldn’t that be exensive!
In wanting to avoid the previous homehowner’s mistake, I may have gone just a little bit overboard. Before buying a single item of water treatment hardware, I first insured that drainage would be all downhill. That plus also not conduct to my septic system at all.
Pre-existing, I’ll route to here as over-flow for in the event of very improbable need. Not that the pump itself necessarily need ever run. My home’s sump pump well exhibits a pair of 6-inch diameter black plastic pipe ends emptying into it. What each of those are is the end of a single pipe called a foundation drain. A good thing to have.
To here is where already directed are the condensation lines from the air conditioner and gas furnace. So that never is the sump pump well dry. Always it is filled with clear water up to the level of those foundationi drain ends. And with almost no sign of iron bacteria clinging to the insides of those plastic pipe ends.
Into here might seem a good place to route softener backwash. Really it’s not, though. At least not on a regular basis. As an auxilliary destination should ever the main floor drain back up for some reason, then the risk is acceptable as compared against spilling onto the basement floor. I have routed my drain pipes to make it so.
As primary drain for softener backwash I have engineered a brand new outlet. Because of the salt, it is all stainless steel. A short length 1 1/4-inch pipe terminating in a 4-foot long well point. This latter is driven only just barely deep enough for its tip to penetrate the water table by about 3 1/4 inches according to my tape measure.
A stainless steel cross at the top allows for inspection and cleanout, both down to the well point, and to the connecting pipe. Threaded PVC plugs block the two excess openings otherwise. Insuring durability against accidental hazard, all non-stainless drain piping is heavy walled Sch 80 PVC.
Just upstream from the floor exit resides an 80-mesh high-volume screen filter. This to prevent the 80-mesh well point from ever clogging. I have a second reusable screen to allow for cleaning at my leasure between inspections. But should the screen ever clog, an 18-inch backup above the highest drain entry leads away at a 45 degree slope to the aforementioned sump pump well.
And above all of that, a drain vent too. Which some might argue is a potential ingress point to allow radon into the house. So maybe I had ought to think about adding a trap. But now that I know how foundation drains work, that would be like closing a louvered door only 1/10th of the way. A quandry to irritate my puzzler well into the future. I’ll order a radon test kit, at the very least.
This feature I mentioned briefly above. In our 1,350 ft2 ranch style home the only visible sign of its presence is inside the septic pump well. Located in the SW corner of the home’s 3/4 basement the sump pump well has, emptying into it the ends of two 6-inch diameter black plastic pipes. These enter at 45 degree angles to the walls. Presumably they are opposing ends of a single flexible pipe with down-facing holes running a perimiter circuit inside of the basement-wall footings, and are embedded in gravel.
A foundation drain serves its purpose mostly during a heavy rain or snow melt. Water sheeting off the roof soaks into the ground near the foundation. Too much of that and it flow beneath the footings. There it finds the foundation drain which provides a path of many times lesser resistance than to well up through cracks in the basement floor. Emptying into the sump pump well solves that problem.
In our house the sump pump well is never less that full of water up to the level of the foundation drain ends. Crystal clear water whose source is condensation from the gas furnace and air conditioner. And not since April of 2013, now eight years past, have I known the sump pump to actuate. That was the year in which April broke a 104-year record for total monthly rainfall. Every farm field I’d pass on my way to work was a lake. Throughout the region, many a homeowner’s basement flooded right up to ground level. My neighbor just lakeward’s back yard was huge shallow pond from a small fountain shooting up into it, outflow from his basement sump pump.
And yet my own basement still remained nicely dry. This without the sump pump ever once turning on. Being higher in elevation by a couple of feet made that much difference. Until, that is, even more rain fell. Then was when I disovered a puddle welling up from my sump to nearly fill the depression around it, plus wetness seeping up through cracks in the floor. That was how I discovered that my home’s sump pump did not work at all.
Which is just as well, considering as how the sump pump’s outflow was plumbed into the septic line. Had it been working, very likely it would have cost me enormously to have my septic drain field replaced.
Various contributors to the Terry Love plumbing forum recommend it as a good idea to periodically shock-treat a well. Below I repost two links from there on how to do that:
From both links combined, I summarize as below:
Chlorine bleach kills bacteria with greatly varying effectiveness depending on the acidity or alkinity of the water which it is mixed into. It kills germs 100% when in a solution mildly acidic (pH 5.5). But that falls down to just 9% if mildly basic (pH 8.1) instead. One must therefore keep tabs on the water’s pH all the while.
Pure distilled water has a pH of 7, perfectly neutral. Water solutions having pH values lower than 7 get more and more acidic. If higher, then more and more basic. A change of 1 in the pH equates to a 10X change of intensity in each direction. So acid with a pH of 3 is 100X stronger than if it were 5. Ditto for bases.
And here’s the dillema: adding nothing but just chlorine bleach to water pushes its pH the wrong way. A chlorine content of 50 ppm rasises pH 7.1 water up to 7.6 such that biocidal effectiveness falls to 34%. Raising chlorine up to 200 ppm pushes pH up to 8.1, reducing its germ-killing power down to only just 9%. Just only its germ-killing power, however. Its oxidizing capacity is unaffected.
To combat this wrong-way pH drift requires also adding some kind of acid. Vinegar works, just make sure it is white (food grade) vinegar, never cleaning vinegar, as the latter has toxic ingredients mixed in. Or else you may choose powdered citric acid pre-dissolved into pure water. Enough of either to pull pH down to 5.5. Not much at all below that, however, as at a pH of 5.0 the chlorine will come out of solution, escaping as gas. An extremely bad thing for that to happen as chlorine gas is horrendously toxic.
Rule #1 is then is to never mix chlorine bleach and acid directly together. Always add them separately into the well, awaiting a goodly interval for thorough mixing in between.
Rule #2 is to acidify first, chlorinate second. The reason for this is that pH test strips get bleached out by chlorine, showing no indication at all.
Rule #3 is to take frequent measurments of both the Cl ppm and pH. Paper test strips can be purchased on-line for both Cl and pH. Know that as the chlorine gets slowly consumed as it does its job. And so it is needful to be adding more bleach to make up the loss. And possibly more acid also, but never too much.
Once the recirculating solution’s pH and Cl ppm are both stable, now is the time to flood it into interior pipes. One at a time, turn on each cold-water tap until smelling chlorine. Don’t let too much of it go down the drain.
Before doing the hot-water taps, the referenced instructions say to re-check the circulating water for both pH and Cl ppm. Be sure to use only Hydrion brand name pH test strips. I had forgot this when purchasing mine from Amazon. Alas and alack, they ceased working at all once I had added in bleach.
The main worry here, is for if the water heater might have a galvanized lining. This because acid is harder on zinc than on copper. That said, however, a mildly acidic solution would do little harm. Worse than acid are oxidizers. And this is what chlorine bleach becomes rather strongly if the solution turns from acidic to basic.
Fortunately, my own Bradford White water heater has a vitreous (glass) lining instead. So mostly it’s just the sacrificial anode that will have suffered. Which, after all, is what it is for. And it is replacable just not easily so on Bradford White models).
The sacrificial anodes which come installed on water heaters need periodic replacement. So long as it has not yet eroded completely away, internal steel surfaces of the water heater are immune to corrosion. Once eaten completely away, damage begins.
On my Bradford White heater, said inspection/replacement required wholly removing the water heater’s exit nipple. A piss poor design.
Purportedly, a sacrificial anode will last 3-5 years. At the 4-year mark, I replaced mine permanently with a 24VDC powered titanium anode. Said powered replacement will last 20 years, performing the self same function even more positively (pun intended). Power is supplied via a 24VDC wall wart, with a ground terminal connecting to the tank itself. Curious as to the current, I measured it at 5.31mA. Power consumption is therefor 127mW (1/70th that of 9W LED bulb).
As a side benefit, the very mild electrical curring running constantly through suffices to inhibit sulfate-reducing bacteria responsible for rotten-egg smell. Of which I had very little, noticable almost never. But as a result now it is gone entirely.
My own well is a 5-inch casement, 42 feet deep, with the pump suspended half way down. And so, with a hose back-feeding it from the top, circulation of the sanitizing Cl/acid solution is mostly only going to happen in that top twenty feet. What’s needed then is to somehow push the sanitizing solution further and further down, all the way down to the bottom and out through the screen into the surrounding earth. Not too very much past that, though, or else one becomes a groundwater polluter.
I have now sanitized my own well. It was easy to do and (pun intended) well worth the effort. I’ll now be doing it no less than once per year. I could wish to have started doing that since buying the house. Results are that good.
My actual labor was only a couple of hours. It all went easy enough except for managing the pH. Once bleach had been added, the pH test strips no longer worked. The bottoming out I managed by first obtaining a big, plastic farm tub into which I pre-mixed the vinegar and chlorine ahead of time. This I was able to do a few feet uphill from my well head. Then I just used a siphon hose to push the solution down the well casement and out through the screen into surrounding sand 42 feet below. For it being a pre-mixed tub, I was able to know the volume exactly.
Admittedly, I got a bit carried away with the chlorine while mixing that tub. Not at all intentionally, but accidentally. I had purchased a crystaline chlorine product for dropping into the casment but was not able to use it for the pellets being too big. They just would not fit. So these I used for pre-mixing the tub. They took much longer do dissolve than I had figured. So even though I was using the test strips, by the time all dissolved, the Cl had got way up to around 200 ppm. Rather too high. Overdoing matters for certain. My pH balance was now surely off, the solution doubtless now oxidizing. And no way at all to know the pH. Counting that as a lesson learned, and with no of thinning it down, I put it down the well casement regardless.
Likewise prior to starting, I had I first set aside three 6-gallon jugs of water to tide us over while the well was out of commission. This worked out to nearly two days. First there was the 12 hour wait while household plumbing, the well itself, and even the soil surrounding its screen just sat steeping in chlorine. Then followed about 18 hours of purging the system clear of all chlorine.
Not just only chlorine, but also quite a lot of gunk. From both of my external faucets I ran 75-foot hoses to separate locations far away from my own well and those of neighbors. I left both of those to run overnight while we slept.
Not until the next morning did I open up taps in the bathroom and kitchen. Immediately, the water from both hot and cold came out an alarming dark gray, still pungent with chlorine. And soon after then, I had to remove the airator screens from both spigots, as these began to clog from collecting many small bits of black grit. From the color, I presume these to be magnetite, a black oxide of iron. It was more than an hour before those taps ran completely clear.
The bathroom tub was a worry for not wanting to stain newly installed fiberglass. So that one I did not turn on until after the sinks were showing clear. Even then I ran into a bucket. Many a bucket did I have to carry outside before I could just let it go down the drain. Last of all, I ran the washer on warm while empty for several cycles.
Even as late as Sunday evening I still could detect a faint whif of chlorine coming out of every tap. (So long as that, without any doubt, because of the 200ppm Cl used for bottoming out.) When finally the odor was down to about the level I judged about equal to standing near an indoor pool, I risked to take a much needed shower. By then the water was perfectly clear with only the chlorine smell an anoyance. It was not until Monday morning that all trace of chlorine odor was gone.
And ever since, for more than a month, our water has run perfectly clear. No iron staining shows in the toilet. No trace at all of H2S odor either. Sanatizing that well is one of the best things I have yet done around the house. For certain, I will be doing that regularly, at least once per year.
Products for descaling generally contain sulfamic acid (H3NSO3), which will likeiwse somewhat corrode into copper, zinc and other metals. Galvanized water heaters are coated in zinc, and so will suffer damage from exposure to any acid (including vinegar). Products which contain a corrosion inhibitor like thiourea (1%), or any filing amine 2%, reportedly minimize such damage.
Strong acids also kill plants and pollute ground water. And so disposal is problematic unless first neutralized. Soda ash can be used for this.
Below are two products made by Aqseptance Group, a division of Johnson Screens, which chiefly manufactures screens used in wells.
NSF certified for potable water well use. Dry pellets of 70% sufamic acid (H3NSO3, one of the ingredients in Lime-A-Way) that sink to bottom of well. A color indicator allow visual monitoring of pH. Product’s SDS does not inform of any corrosion inhibitors. Advertised to clean calcium and magnesium carbonate scale, iron deposits and moderate biological growth.
Per Wikipedia, When compared to most of the common strong mineral acids, sulfamic acid has desirable water descaling properties, low volatility, and low toxicity. It forms water-soluble salts of calcium and ferric iron. Sulfamic acid should not be combined with chlorine bleach as it will scavenge the hypoclorite ions (although without producing clorine gas in the process).
An Ace Hardware store local to me sells single-treatment doses portioned separately out from a bulk container, which is how I learned of it. Seems like a lot less fuss than chlorine shock-treatment. Especially as my bacteria issue is entirely just the iron- and sulfate-reducing types and not any of the coliform variety.
On the Terry Love plumbing forum, however, neither this nor any other pelletized or granular product came recommended. Not unless it was first dissolved into water and introduced to the well as a liquid. This in sufficient quantity so as to drain down through the whole well right to the bottom and thence through the screen into surrounding soil. Also cited was price, a total cost considerably more than would buy an equally effective quantity of germicidal bleach and vinegar.
NSF approved for cleaning potable water wells, pipelines and filter systems. A liquid product blending organic acids, potassium hydroxide (KOH) <3%, dispersant polymer, surfactant, and water. Dislodges biofilm masses associated with iron oxidizing, sulfate-reducing and more prevalent slime forming bacteria, which are not removed by mineral acids alone.
Product’s SDS states for professional use only, recommending face shield, goggles, gloves, and protective clothing. I’m glad to not be needing this one. I am curious, though, how it can be that 3% KOH can co-exist with acids and not be completely neutralized.
An engineering report PDF by Najwa Majeed (University of Baghdad) compared these two acids for de-scaling effectiveness. The former proved notably better.